Uboat, are you assigning an Euler XYZ Controller, after you have assigned an ArgBased Rotation?
In not, you need to do so.
If so, sometimes max gets funky. It happens to me once in a while.
You'll have to remove the animation,
Remove the argbase rotation.
Assign a default controller "linear rotation"
Reset the xForm
Adjust your pivot if necessary
Reapply the argbase rotation and then assign a euler xyz to that argbase rotation.
animate your door
rexport and test.